Zinc is an essential element to our well-being. Zinc acts as a catalyst in about 100 different enzyme reactions required by our body, and is involved in DNA synthesis, immune function, protein synthesis, and cell division. It is required for proper sense of taste and smell, detoxification, wound healing, and thyroid function. Zinc is not stored in the body, thus a daily intake of zinc is required to maintain sufficient levels.
One in four individuals in the general population may be zinc deficient, and most people with hypothyroidism are in fact zinc deficient. Zinc deficiency prevents the conversion of T4 into the active T3 version. This perpetuates the vicious cycle by a slowed metabolism of proteins.
Zinc is also needed to form TSH, and may become depleted in those with hypothyroidism who are constantly producing more TSH.
Zinc deficiency has also been associated with increased intestinal permeability and susceptibility to infections as well as reduced detoxification of bacterial toxins.
Oysters have the highest concentration of zinc, but they are not something most people would enjoy eating every day. Beef, liver, pork, lobster, and chicken are the next best sources of zinc, as it is easiest to extract zinc from meat compared with non-meat sources. Thus, vegetarians also have an increased risk of zinc deficiency.
Absorption of zinc may be impaired by damage from intestinal disease such as celiac disease and other malabsorption syndromes. Phytates found in grains, legumes, nuts and seeds can bind zinc and prevent its absorption when eaten alongside zinc containing foods. Taking iron supplements in conjunction with meals may also prevent the absorption of zinc from food.
Zinc deficiency can show up on a liver function blood test as low alkaline phosphatase levels. The importance of alkaline phosphatase will be discussed in further detail...
In order to address deficiency, zinc supplementation may be utilized, with doses of no more than 30 mg per day. This is because Zinc supplementation above 40 mg may cause a depletion in copper levels. If choosing to take zinc, one should also take a copper supplement. Usually 1.5 mg–3 mg of copper should be sufficient. (General recommendations are to take 1 mg of copper for every 15 mg of zinc).
Caution: Zinc can cause depletion in copper and iron. Fifty milligrams of zinc given over ten weeks impaired both iron and copper absorption in one study.
Symptoms of copper deficiency are: anemia not responsive to iron supplementation, trouble with walking and balance, fatigue, and light headedness.
Not all supplemental zinc formulations are created equally...I prefer the Zinc Picolinate version because it is absorbed better.
To ensure proper absorption, Zinc supplements should be taken with food.
Check out my other posts
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Nutrient Depletions Part I: Selenium
Nutrient Depletions Part II: Nutrient Extraction
Nutrient Depletions Part III: Hair Loss and Thyroid
Nutrient Depletions Part IV: B12
NOTE: These statements have not been evaluated by the Food and Drug Administration. The products discussed are not intended to diagnose, treat, cure, or prevent any disease.
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Izabella Wentz, PharmD
1. Daher R, Yazbeck T, Bou Jaoude J, Abboud B. Consequences of dysthyroidism on the digestive tract and viscera. World J Gastroenterol 2009; 15(23): 2834-2838 Available from: URL: http://www.wjgnet.com/1007-9327/15/2834.asp
2. Wada L, King JC. Effect of low zinc intakes on basal metabolic rate, thyroid hormones and protein utilization in adult men. J Nutr 1986;116:1045–53.